


The Path to Paradise begins in Hell

by loosingletters



Category: Ao no Exorcist | Blue Exorcist
Genre: Bad Parenting, Body Horror, Cannibalism, Children, Codependency, Dysfunctional Family, Family Drama, Gen, Gore, Implied/Referenced Child Abuse, Insanity, Mind Manipulation, Nonbinary Character, Other Additional Tags to Be Added, alternative universe, demonkingsweek2k17
Language: English
Status: In-Progress
Published: 2017-11-25
Updated: 2018-09-28
Packaged: 2019-02-06 15:26:57
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence
Chapters: 9
Words: 8,216
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12820473
Author URL: https://archiveofourown.org/users/loosingletters/pseuds/loosingletters
Summary: In one world Samael and Lucifer were at each others’ throats. In this one, Lucifer is old and tired and just wants to be able to breathe.And when Samael presents him with two children, calling them solutions, Lucifer isn't quite sure if his brother knows what raising children entails.Or that one AU in which all demon kings can more or less stand each other, Satan is the end boss and Rin and Yukio are raised by their older siblings.Written for Demon Kings Week 2k17!





	1. Lucifer

**Author's Note:**

> So, actually, I had planned to write a fun AU with is 90% bad jokes and 10% Lucifer drinking coffee.  
> Somehow it got a little darker.  
> Anyway, I hope you enjoy this story! I'm not sure if I can get all days done because it's exam time for me again (yaaaay -.-) but I'll definitely finish this ten-chapter project!

Sometimes he felt far too old for this world. He’d watched kingdoms rise and fall; he had dedicated his precious, always scarce time to so many different causes, each of them promising him to cure his aching bones, his sore joints, his collapsing lungs, his raw skin, the decaying of his being.

And every ten years still he drowned in his own blood and woke up in a body foreign to him for at least another year until the suffering would start again and the familiar pain would return.

Lucifer was tired of living but even sicker of dying.

Perhaps that was the reason he had agreed to Samael’s offer so easily, not even caring to negotiate the details with him, certainly a dangerous mistake to make when dealing with the King of Time. But Lucifer wanted to be able to take a breath without starting to cough and eat real meals without vomiting.

If he had given this project of Samael more consideration, maybe this situation could have been avoided.

“Their names are Rin and Yukio,” Samael said, for once abandoning his foolish demeanor and acting like life was more than a simple game of chess whose outcome he’d predicted before it even started.

Lucifer studied the newborns lying innocently in their crib. If he were younger, say Astaroth’s age, he wouldn’t believe them to be anything but two human children with pink skin and black hair. Sleeping together like this, curled around each other, they appeared to be far from the tragedy they were sure to become.

“They’re not human. What are they?”

He didn’t take his eyes of them, wondering why it was so hard to tear himself away from their sight. He wasn’t waiting for chaos to come crawling out of the corners, though the chance of that happening was rather high considering they were standing within Samael’s home, but still there was a pull drawing him to the twins.

“I don’t know,” Samael admitted, frowning. “They are from Gehenna but not off Gehenna, not in the way we are.”

Lucifer turned to his brother, wincing as his side stung him sharply with what felt like razors. His painkillers were wearing off again, he needed to take his next dose soon if he wanted to get some shut-eye.

“What are they?” He pressed.

“Children.”

“ _Whose_ , Samael!? Don’t play games with me. Not now.”

Samael’s eyes flashed dangerously but even so, he just laughed drily and didn’t hesitate to answer.

“Its, his, Gehenna’s, Satan’s or whatever name it has decided to go by now. Apparently, the Ego of a world can develop beyond the boundaries of one plain as long as its thirst for more is saturated, which it never will. Demons are never content, we’re always starving. These two are ‘Plan B’ as far as I can tell. They contain the same power, if weaker, within them. That power is sure to grow beyond everything even my seals could control. They are basically Gehenna's failsafe if I can keep it from opening a Gate to Assiah; the perfect vessels.”

That plan sounded just mad enough to hail from the world they kept trying to escape.

“We can’t let that happen. Why have you allowed them to stay alive?”

Murder usually wasn't Lucifer's first choice of action but already the existence of these two innocent beings risked the safety of Assiah. It would be unwise to let them live and grow up to be Gehenna's perfect puppets.

"Because of all the possibilities these two promise. They are similar to Gehenna in all but one; they are part human. They were born in Assiah! Imagine what we could do with that, Lucifer. The cores of a world in a stable human shape. All we need is for them to grow up ready to use that power."

Samael grinned like a shark, revealing the dangerous predator hidden behind the mask of a trickster.

"What are you planning, Samael?"

"I'll put a new king on Gehenna's throne and you will teach them how to do more with that crown on their heads than to simply show it off. I know you remember the fall and the shaping of Gehenna."

Oh yes, he remembered the burning of his fingers as they dug them into the darkness of nothing in particular; shaping, creating-

"You're cruel, brother," Lucifer said and stepped closer to the crib again. He reached for the fussy twin and lifted him up, gently cradling the babe. "Ruining their lives like that."

Samael snorted. "Like you care about them beyond the possibility that they might be able to relieve you from your pain."

The child calmed down and soon his breathing was even again.

"I never said I had any moral high ground."

He returned the child to his brother and, with one last glance at the two, left the room behind, his legs feeling like they wouldn't carry his weight much longer.


	2. Samael

**Summary for the Chapter:**

> Samael wants to destroy Gehenna. Unfortunately, his weapons so far are still learning how to crawl. Lucifer’s attitude towards the children wasn’t helping either.

**Notes for the Chapter:**

> Next chapter! I feel like I should mention that this will cover the twins growing up but please don't expect a 60.000 word novel. It'll most likely be beneath 8.000.

Samael was entirely unimpressed with the two children drooling over his carpet as they intended to crawl over to their oldest brother. Lucifer, on the other hand, was positively delighted to see the children take so well to him. Of course, he denied it but the faint smiles Lucifer probably wasn’t even aware of, gave him away.

“I don’t think I can take another ten years of them ruining my carpet,” Samael said from his comfortable armchair in the corner of the living room.

Lucifer pulled Rin, the faster, older and so far more impressive annoyance, on his lap and reached for the pacifier lying on the coffee table. As soon as Rin saw it, he tried to get a hold of it with his pudgy little arms.

“They’re not even a year old, brother. Surely you must have known how much time would go into your plot?”

Lucifer really could do without the condescending tone.

Samael rolled his eyes. “I’m not a hot-blooded brat like Amaimon. I’ve been patient for millennia, I can wait a decade.”

Lucifer smiled pointedly at him before turning his attention back to the twins, especially Yukio as he now too had reached the demon.

He knew children had to be treated with care otherwise they’d wither away, but still, Samael wondered if Lucifer wasn’t raising them overly gentle and loving. Certainly the boys didn’t need to be with him every hour of the day and Samael had more than enough servants in his home which could watch them. But Lucifer denied all his suggestions and became the maid himself either way. One of these days Samael would catch him dressed in sweatpants instead of the more formal wear his brother used to prefer.

“They’re not Castor and Polydeuces,” Samael decided to speak up again, eager to see his brother’s reaction.

And there it was, the twitching of his shoulders, the holding of his breath, the glaring-

Toying with his siblings had always brought a remarkably satisfying joy to him. He wasn’t even particularly mean with his taunts. They weren’t hitting anywhere too deep, or at least they shouldn’t.

“That was a low blow, brother,” Lucifer replied. “But seeing that Rin and Yukio should go to bed now either way, we’ll leave you alone. Good night.”

Lucifer picked the boy up, first Yukio, then Rin, holding them with no problem at all. Ages ago he wouldn’t have shied away from this confrontation. They’d been less exhausted more hungry for blood back then.

“Sleep well,” Samael told him and watched his brother disappear down the hall with the children.

Lucifer really needed to take a break from the brats; their pull on him was too strong. Perhaps he needed to check their seals again? Their allure couldn’t start to show again already.

Or maybe the problem was his brother and not Samael’s seals.

Sure, Lucifer had only ever fathered a few children but he had had them. But certainly he couldn’t have bonded so thoroughly with them? How strange, Samael had never felt particularly attached to his hellspawns beyond their usefulness. Then again he had never taken it upon himself to raise his children. Perhaps he should speak with Iblis. He managed to nurture himself great vessels without any emotions getting between him and his goals.

Samael frowned as he poured himself another cup of tea.

Iblis was busy pampering his current next vessel, wasn’t he? And the child was barely older than the twins, perhaps an older playmate would teach them to become more useful and put themselves to bed.

Content with himself, Samael rose from his chair and retreated to his own bedroom, but not before he nearly fell over a lego block.

**Notes for the Chapter:**

> Also! - very important - I think I should explain what I was thinking when coming up with this idea?  
> I thought that since Satan = Gehenna and his defining power are the blue flames, Rin and Yukio possessing the same powers should make them more than regular demons. In fact, they have the power of what shapes a whole realm. Ergo Mephisto's hoping that with their abilities they can modify Gehenna or Assiah in its core to be able to host demon kings with bodies and their egos intact.  
> That's basically it.


	3. Azael

**Summary for the Chapter:**

> Lucifer continues being the twins' *cough* mom *cough* guardian and Azazel talks a lot.

**Notes for the Chapter:**

> I told you all I would finish this so here is the next chapter!

Azazel met his youngest brothers for the first time when they were five and curious. Lucifer held each boy’s hand strongly and barely let them leave his side on the way towards Azazel’s resting place. It was entertaining to see the eldest so emotionally comprised.

“Is that him?” Rin asked, pointing at Azazel’s intangible body. “It feels like him.”

The other boy’s furred his brows and focused his bright blue eyes on Azazel. “It looks like him too.”

Both look up to Lucifer, eagerly awaiting his confirmation and praise.

“You’re right,” the King of Light said. “This is our brother Azazel, King of Spirits.”

The boys took a step forward, towards him, hesitating only in the last second. Their shoulders tense, visible even through their thick winter jackets. Then, as so often already in the last minutes, they turned to Lucifer again. He nodded and that was apparently all it took for the twins to storm to the remains of his vessel. They immediately began to tell him about their lives and hobbies and training. Azazel would by no means claim to be the most human of his siblings, but even he was unsettled by Rin and Yukio’s stories and how little the two seemed to care about their own wellbeing.

“You’re raising puppets,” Azazel told Lucifer. “What will you do with them when they have served their purpose?”

He had spent more time with humans that most of his siblings. He had studied them, their behavior and mannerisms and had learned from it. As much demon blood as the twins in front of him carried, they were human at the core. It didn’t take much genius to see that, just the ability to reach into the depths of a soul.

Rin and Yukio were still chatting, unaware that he had chosen to strike up a conversation with Lucifer. He thought it was kinder to leave them to their happiness than to reveal he wasn’t listening to them. It wasn’t like they could hear what he and Lucifer discussed. Being the King of Spirits had more advantages than surviving in Assiah without outside help.

“I don’t know what Samael is planning.”

Azazel bristled in anger. “You don’t know? You have become careless, Lucifer.”

Careless and numb. In silence he wondered where his bloodthirsty brother had gone. Where was the King of Light who marched into the room with the screams of war following him?

“I’m not supposed to care. I am to raise them and teach them what I know of Gehenna’s creation so that they can fulfill their purpose.”

Azazel dug his claws into his brother’s mind, a sharp reminder of his usual bitter laugh.

“I forgot the boys’ lives have been predestined before they were even born. Created to be our cures.”

Lucifer’s footing strengthened as he braced himself for the confrontation. “They weren’t created for this purpose. It is simply an opportunity which has opened up with their birth.”

“Oh, please,” Azazel laughed. “You don’t even believe that yourself. Do you really think that Samael would let the situation escape him so much that such an opportunity would simply arise? Open your eyes, brother. Our cures have been bred and cultured like Amaimon’s vessel. You better keep them close or they’ll drown.”

With that Azazel retreated from Lucifer’s mind and returned to paying his attention to Rin and Yukio. Testing Lucifer’s patience any further would be like poking a sleeping bear, perhaps funny at first but dangerous all in all.

And he rather liked the two boys, they were almost too cute and reminded him a bit of his own children.

Perhaps he should visit Shirou again. It had been a few years since he had last reached into his progeny’s mind.

With this Azazel slowly drifted off again, his conscious shattering once again and running away with the wind.

**Notes for the Chapter:**

> Lucifer is not as unknowing as Azazel thinks, he's just very apathetic and can't find it in himself to care.  
> He's tired.  
> And depressed probably too. I should probably tag that.  
> Until next time!  
> Leave your thoughts behind on your way out, please!


	4. Iblis

**Notes for the Chapter:**

> Warning for implied maybe incest? I have no idea how demon dna works. It's not between our main characters here though, rest assured.

Iblis prided himself on being the only demon who truly understood humans. His siblings all could bicker, pretend and make plans to take over the world by manipulating the weak flesh bags into working for them, but the fact was that Iblis was the only one who took the time to learn how humans worked and gained an understanding for their motivations, actions and behavior.

Of course, he didn’t do it because he was interested in them or liked them. After thousands of years he was fairly sure he couldn’t even grow to harbor any positive emotions towards anyone or anything besides himself. No, Iblis was too full of himself. How could he not? He was fire and fire did nothing but burn, consume and annex.

He was hungry for power and humans were so willing to give once he understood their motivations. After all, the most exceptional gift they could give him, were themselves. Their bodies, their places in Assiah. Iblis may not burn through a body every ten years like Lucifer, but fast enough that waiting for an opportunity to get a hold of a proper vessel was a hassle.

That, above everything else, was the reason Iblis had learned to understand humans. If he wanted a human body, and he desperately needed one, he had to know how to get humans to make him one. Over time he had assembled a few loyal and old families. He shared his wisdom, strength and influence with them, and in turn, they provided him with somebody to share his genetic material with, once it was the time for it, and grow his own vessel.

Azazel had called it barbaric, possessing his own children, having children with his own descendants. Iblis called it efficient. He was becoming stronger with every generation; his bodies lasted longer – what more could he wish for?

Sure, not having to change vessels at hall would be the dream, but it only took one look at Samael’s solutions to know that the older demons plan would never work.

“Kaito! Kaito! Play with us!” His younger brothers shouted, pulling at Iblis’ next vessel.

Kaito turned to him, silently asking for permission. Iblis liked the boy. It was a shame he’d erase him in a decade. The King of Fire nodded and the boys ran off, but not before twins shot him glare.

Iblis grimaced, all teeth and no fun.  Give it a decade and he’d smile like that again, watching his brothers’ carefully made plans fall apart.

Iblis was a demon king. He knew humans and he knew fire.

Rin and Yukio, as much as Lucifer pampered them and prided himself on their successes and believed they’d be his cure, would be neither his salvation nor Samael’s weapons.

The twins were humans given the power of Gehenna’s brightest flame but it would never be enough for them. They were young still but Iblis could see what they would grow up to be like: possessive monsters wanting to consume and being scared of every burn mark they’d leave behind.

Perhaps they would dethrone the Ego currently shaping Gehenna, but definitely only to take the palace for them. If Samael believed he was raising puppet kings, he was a fool.

Iblis was raising a puppet himself, simply by comparing Kaito to the twins he could tell that Gehenna's next kings weren't going to be dolls. They had too much personality and pulled everyone they met into their circle.

He wouldn’t be able to change into his new vessel easily if he let Kaito stay around the twins. Their magnetism was too strong.

“Kaito won’t visit again,” he told Lucifer later. “But I’ll stick around. It’ll be interesting to see the results of your experiment here.”

Iblis didn’t believe in the new world Samael and Lucifer hoped to create. He only wanted to see if, in the end, Rin and Yukio would take the world down fighting against each other to proof each other’s strength or if they would break apart because of their weak humanity.

**Notes for the Chapter:**

> I told ya I would finish this and I will. So, here, take Ilbis.  
> Kaito is one of my OCs I made up for my story "Fire burns twice" - time travel AnE OS!


	5. Egyn

**Notes for the Chapter:**

> Time jump! The twins are 13 now and show their first signs of "Well, Samael, maybe your plan was a fucked up idea"

Egyn wasn’t sure why they had to be the one to patch their youngest brothers back together again, but they guessed it had something to do with Rin and Yukio being absolutely terrible patients. Egyn much preferred the times when they had been working in Lucifer’s labs under more comfortable conditions. The twins’ antics weren’t something they could just ignore or immobilize with morphine. Though, Egyn grudgingly had to admit that the later probably wouldn’t work after the twins came back from Lucifer. After hours spent in what had been dubbed their _‘playroom’_ , the twins were too hyped up for the needed morphine doses being anything but lethal, never mind their mental state.

Egyn would never admit it out loud of course, but the twins frightened them. They came back too synchronized, too demonic, too much like Gehenna for Egyn to be even remotely confident around them. In moments like these, their allure seemed to draw even them in, and Egyn was a demon king for crying out loud. Neither a half breed nor some week middle-class demon; they were part of the strongest, a part of Gehenna itself!

And perhaps in that laid the reason for their downfall.

“Egyn, Egyn,” Rin called, drawing out the vowels like he was trying to say their name for the first time.

“Yes, Rin?” They replied, keeping their gaze down on his arm and the syringe slowly filling with blood.

“You love us, don’t you?” Yukio continued for his brother. “You’ll stick with us. You won’t run away and leave. When we take the crown, you will be there.”

“Of course I will be there,” Egyn said, wisely refraining from answering the first question. Everything within them screamed that it was a trap. In fact, nothing of Yukio’s statement reminded Egyn of a question. Every word he spoke was a command, a demand.

If Egyn could look at the situation with as much humor as Iblis could, they would laugh at the twins’ behavior. Samael and Lucifer were raising excellent monarchs. The two thirteen-year-olds heirs of Gehenna were precisely what you could wish future sovereigns to be, except they hadn’t wanted superior beings, had they?

“You have to promise,” Rin insisted and in one swift move grabbed Egyn’s hand and pulled them closer.

Forced to look up from their work, Egyn’s attention was immediately captured by bright blue eyes. Rin’s eyes hadn’t looked like Yukio’s last week, Egyn was sure. He had taken after their mother, Yuri Egin, in that aspect. Egyn would have to put that in the report as well. As small and minor that discovery was compared to the other changes the twins had gone through in the past years, it was still their job to write it down.

If only they could look away.

“You’re keeping that promise, right?” Yukio took over again. He was taller than Rin, and while neither child was a giant, he still towered over Egyn.

And it was in that moment, that saying yes seemed so natural and like the right course of action to take. After all, the twins would rule someday and who was Egyn to question that. Rin and Yukio would be grand, and all consuming and all giving and all Egyn had to do was give in and return-

“I-,” before Egyn could reply, the door to the room opened and Yukio and Rin sat up straight, widening the distance between them and Egyn again.

“Are you done?” Lucifer asked and Egyn used the moment to close their eyes and take a deep breath.

While such human options of calming down were almost useless given their superior sense, Egyn could still feel the connection the twins had built up – and there was no questioning that they had forced it upon them. They’d have to tell Lucifer, he needed to know that their cures were getting out of control – but now also actively shatter it. Once upon a time they wouldn’t have to destroy any kind of bond because there would be nothing that could have drawn them in.

 “Yes, I’m done,” Egyn replied and hastily collected their things.

The moment Egyn’s body would be fixed, they’d leave and run as far away as they could. They couldn’t wait for all of this to be over, though they wondered if such a phase would ever come or if this path they had chosen could only end in damnation.

But it wasn’t like a demon who had only ever known hell could really tell what perdition was when they had never gotten a taste of heaven. Maybe they should ask Lucifer, he would know even though his judgment was clouded by the insanity of Samael’s plan.

“But you didn’t even draw my blood,” Yukio protested.

Maybe Egyn should just punch him and die before it could all spin out of control later.

“I don’t need to today. Now go, you’re free for the day.”

Egyn wanted them out of the room, out of their life for the next seven days until they had figured out how to deal with Rin and Yukio.

“You heard your sibling, off you go,” Lucifer told them.

The two thirteen-year-old sighed and just like any other teenager walked out of the room with freaking pouts on their faces. They didn’t look like monsters anymore, their faces weren’t twisted impressions of Gehenna. Had Egyn just imagined it all?

Lucifer looked over Egyn’s half written report, frowning for a moment before his expression took on its usual unimpressive mask.

“Egyn, we will talk tonight.”

The King of Water just nodded, not letting the twins out of their eyes until they were finally gone. They were both almost out of the door again when Rin spoke up.

“Heaven’s not all that different.”

Iblis was a fool, of that Egyn was sure now. They were right to be frightened of their siblings. Nothing about this situation was even remotely amusing. This was the apocalypse waiting to happen.

And there was no escape.

**Notes for the Chapter:**

> Thanks for reading!  
> More explanation on what training the twins are doing will come next time!


	6. Astaroth

**Notes for the Chapter:**

> WARNINGS FOR GORE  
> This is the chapter I didn't want to write because I thought it would bore me to death and while it took long, it somehow turned out fun and is I think the longest chapter here.

“What do you need me here for again?” Astaroth asked, turning away from the glass wall separating him from his allegedly youngest brothers.

The King of Rot wasn’t buying into the whole new-siblings-gig, even if the two hellspawns were currently unsuccessfully trying to burn each other’s face off with Gehenna’s royal flames. Or maybe they were attempting to play with each other given the smiles on their face. Astaroth hadn’t made it his habit to spend time around children or teenagers or any human really.  All of his kin and his consciousness were constantly surrounded by the atrocity of human nature, he didn’t need to meet them in the flesh as well thank-you-very-much.

But here he was, away from his hideout and dressed up as well to look presentable, to interact with messed up abomination. His long hair had been brushed and braided, and he had been stuffed into a suit.

For what audience he didn’t know, certainly not for the half-feral brats in the room next to him. Probably for Samael or Lucifer’s amusement. His eldest brothers were obsessed with luxury, bathing themselves in all the glory Assiah had to offer so they could wash away Gehenna’s taint. Astaroth’s appearance was probably a bit like a personal offense to them.

“We don’t need you specifically, just your kin,” Lucifer answered. “We’re testing the Rin and Yukio’s ability to absorb demons to gather more power for themselves. And for that, we need a lot of demons. You just happen to have the most.”

“The most pigs to spare, huh?”

Astaroth was the odd one out of all his siblings, given that he didn’t really have an aspect of his own. What was rot, if not the passage of time? He was essentially a weaker copy of Samael, but unlike the King of Time, he couldn’t count the number of demons under his command with two hands. The sheer numbers of his underling were what made Astaroth strong, as well as their variety.

Decay, weakening, rot, infection, and disease were present within every human, every living being. Taking control of them was almost too easy.

No, Astaroth wasn’t strong, but he was many. Besides Samael’s, his bodies always lasted the longest. And even while they were falling apart, Astaroth was always reaching the height of strength in his last year, drawing power from his own unbecoming.

“Will you help us?” Lucifer asked, and if Astaroth were a lesser being, perhaps a hot head like Ilbis, he would have refused given Lucifer’s haughty tone.

“Why do they need to learn this in the first place?”

Lucifer’s expression matched a sour lemon, venom lingered in his eyes and a sneer on his lips. Astaroth pretended to be unaware of his older brother’s annoyance and patiently waited for his reply. He was good at waiting, staying patient and outlasting. Eventually, everything fell prey to his nature, even the King of Light.

“They need to learn how to balance each other,” Lucifer finally gave in. “They tend to become… self-destructive after too many demons.”

“How many?”

“Currently we’re at twenty. Do you want to see?”

Of course, Astaroth wanted to see. If he was supposed to sacrifice his demons to a shady project he wasn’t even convinced off, he wanted to know exactly what he had in front of him.

Lucifer walked over to the control board standing right in front of the glass wall and pressed a couple of shiny buttons. Within the white cell, a small door opened. The two boys immediately stopped playing, and grotesque impressions of mischievous smiles took over their faces.

Yet they didn’t move from their positions, only their heads turned into the direction of the door. Soon after an averaged sized hobgoblin crawled into the white cell. It was barely out of the tunnel, before one of the children already jumped towards the hobgoblin, digging his sharp claws into the demon’s soft flesh.

Hobgoblins weren’t particularly strong, but they should be more resilient to the hands of a mortal. However, the boy slowly worked his way into the demons body, curiosity and wonder sprawled across his face like a child on Christmas day. Then he cried out in joy and ripped something from the demon’s body, the slightest hint of blue dancing along his fingertips.

“Is that…” Astaroth trailed off, staring at flesh in the boy’s hands.

“The hobgoblin’s heart, yes,” Lucifer said.

Astaroth kind of wanted to punch his older brother and wipe that bored expression off the blonde’s face.

“They tear it out and eat it. Whoever gets to the demon first, gets the spoils. It didn’t matter at the start, but nowadays Rin and Yukio don’t really like to share with each other anymore, and instead of letting the power flow from one end to another and share that energy, they try to keep it for themselves.”

As if to proof Lucifer’s point, the other child reached for his brother’s hand and the heart and tore it from him, quickly devouring it.

“Rin!” The robbed boy hissed his brother’s name and with one swift move started to attack his brother.

Their brawling was impressive, Astaroth had to admit. Blue flames heated up the hair as teeth and nails tried to get a hold on the other and tear him to shreds.

Lucifer sighed and absentmindedly reached for the remote lying innocently on the table next to him. It only had three colored buttons, green, yellow and red like traffic lights, and Lucifer pushed down the yellow button. Immediately the two boys stopped fighting as their bodies began to twitch and after a moment they dropped to the ground, unconscious.

Unceremoniously, Lucifer turned away from the glass window separating them from the twins to face Astaroth with an expectant expression. Lucifer had always been like that, demanding, assured that everybody would ask “How high?” if he said “Jump”. Most of his siblings were so used to getting what they wanted, and even if they claimed to be patient, they would never really know what it meant to wait.

The two children behind the glass were just the same. Impatient little hellspawns that wanted more and more and could never be sated.

“So, will you help us?” Lucifer asked.

Astaroth, however, knew what it meant to wait. His entire existence revolved around the passage of time. And in the end, everything would pass and rot away and make him strong. Especially the two powerhouses in front of him.

“Sure,” Astaroth said. “If you can teach them how to share beforehand.”

Lucifer glared at him, already ready to lash out and snarl at him. For once, Astaroth indulged in a little impatience and spoke before his brother had a chance to.

“I am many, Lucifer. I’d get jealous all the time of myself if I hadn’t learned to share.”

“So what do you want me to do?”

Astaroth observed the unconscious twins. Asleep as they were now, without their demonic appendages, they almost looked like normal humans.

“They are still somewhat human, aren’t they?” It was hard to believe after that display of power, but for them to exist in the way they did they must be partly human still. “So send them to school. Humans learn there.”

Lucifer stared at him like he had grown a second head and Astaroth enjoyed every second of it. If he’d have to choose a memory to preserve for eternity, it would undoubtedly be the flabbergasted look of the eldest demon.

“You want me to send Yukio and Rin to the outside world so that they can learn how to share like toddlers?”

Astaroth shrugged, crossing his arms over his chest with a thoughtful expression

“Well, you obviously failed in that stage of their development if they don’t know how to share. Samael has his cute little exorcist school, go send them there. They’ll still be in a controlled environment, but free enough to explore what interaction with other beings mean. They need to learn how to be part of a system with immediately seizing command and destroying everything in their vicinity. That might have worked for you, Lucifer, but that won’t work for them.”

Lucifer mustered him a while longer as his expression changed between annoyance, anger, fascination and a multitude of other emotions within the span of seconds as he considered Astaroth’s suggestion.

“Fine,” Lucifer finally agreed. “But we will start training parallel to their school time, not afterward. We don’t have much time.”

Astaroth hummed in appreciation and returned to observing the twins. They’d learn and grow, and someday they would fall and decay. And then Astaroth would be there to collect their pieces and add them to himself.

Nobody was immortal and all-powerful, and Astaroth was patient.

**Notes for the Chapter:**

> Next chapter we will get fun twins who are coherent and doing stuff and not high on Gehenna's flames I promise.


	7. Amaimon

Amaimon looked around the classroom, bored by the humans’ fear and squishy bodies. Samael had promised him that it would be _interesting_ , that he’d have _fun_ and be provided with lots of entertainment. So far he didn’t feel particularly much of anything besides boredom and some anger at being pushed at this banal task. Of course, it had to be him who was forced to play babysitter for Rin and Yukio because obviously, he wasn’t busy at all.

It wasn’t like he had a garden of significant importance to tend to, a balance he needed to provide and miasma he had to filter. He was the King of Earth, and the only one who possessed the ability to keep demons from harming Assiah. More even, his kind was enriching Assiah’s power, unlike Astaroth whose symbioses with Assiah resulted in him reveling in destruction. Sure, everything passed away some day but infections were terrible diseases destroying this world they wanted to own someday.

But all of that wasn’t important, right? Because he wasn’t actively busy with Samael’s or Lucifer’s plan.

Amaimon bit down on his lollipop, crushing the candy with his teeth.

At least Amaimon wasn’t totally alone in this mess. He chewed obnoxiously loud on his candy, waiting for Azazel’s clone to lose his temper. Amaimon had always liked messing with Shiro, he was fun to annoy and to spar with. Sure, it had been done so that Amaimon could adjust to his new body, and therefore it hadn’t been a serious fight, but he had enjoyed the exercise and the clone’s fool mouth either way.

“… and now they will introduce themselves.”

Everybody’s pitiful attempts to sneakily stare at the trio disappeared as they now openly gawked at them. These brats wouldn’t survive a day out there in the real world, Amaimon thought. Shiro ought to teach them like he had been: how to wield chaos and destruction and make it your bitch.

Amaimon swallowed his candy and liked over his lips, savoring the sweet taste still lingering.

“I’m Ambrosius Faust. Don’t piss me off,” he introduced himself and stuffed his hands into his pants’ pockets.

He wasn’t here to act human, to make friends or whatever. He certainly wouldn’t our more energy into this task than absolutely necessary. Out of the corner of his eyes, he watched as his younger brothers fumbled through their own introductions.

“I’m Faust Rin and this is my brother Yukio.”

Fitting with their made believe back-story, the twins were dressed neatly in their ironed school uniforms with shiny silver watches of some high priced brand Samael had talked about adoring their wrists. A simple glamour hid away their sharp nails and teeth, as well as their pointy ears. Like proper demon royalty, their weaknesses were tugged away.

Amaimon could almost see why it might have been smart to assign a babysitter to them. They looked the part, but their behavior was miles away from passing as human.

“Nice to meet you,” Yukio continued, blank face and dead-eyed.

They definitely needed someone to watch over them, but Amaimon was definitely the wrong demon for the job.

Some of the humans seemed to take their introduction personal, like the three of them had just committed a grave offense. But Amaimon didn’t care about humans and all their subtle mind games and tricks. He was also quite sure that no other demon should play according to their rules, no matter how much joy that could apparently bring them – but Samael had always been a freak like that. Demons were superior to humans in every possible way. They should be the ones determining the laws of this world and every other they could ever get their hands on.

That was the only reason he couldn’t wait for this whole plan to be finally over. No more Father to tear them to pieces, no more Assiah wearing their bodies down. They’d finally be truly free from everything that caged them.

Well, as long as the twins learned how to be human or whatever. He didn’t understand Astaroth’s reasoning. To him, it sounded like the elder was trying to waste everybody’s time by contradicting every lesson they had more or less carefully taught the two boys.

They were supposed to replace Gehenna someday, you kind of couldn’t get any more demonic than that – what use was human behavior in that equation? Demons didn’t share, they didn’t care, and they most certainly weren’t selfless.

This whole trip would be the most useless event in the boys’ already short lives.

Amaimon was sure that Shiro’s thoughts weren’t dissimilar to his own. The clone had quite the hard time to look at the twins like they were just another pair of students. Of course, nobody had expected him to treat them like normal teenagers. In fact, they had been assigned to his close precisely because he would be able to deal with them long enough to ensure nobody would die too fast should they get out of control.

Yet that wasn’t everything there was to Shiro’s troubled expression, was it?

“Alright, take your seats now,” Shiro announced and pointed towards the empty seats. “You can sit down wherever you want, but I’d prefer it if you stay close to the front rows.”

Amaimon reached into his pants pocket and took out another lollipop as he marched to the desk the furthest away from Shiro and the front row. The clone raised a brow but didn’t say anything. Good for him, Amaimon had no problems making his opinion on this whole situation known by more drastic means. He liked solving his troubles with violence. It was stronger, easier and much more efficient than talking down your enemies or whatever. Nobody besides his siblings could keep up with him anyway, so why bother speaking to his inferiors?

Rin and Yukio though, perfectly obedient little brats, did exactly as told and next sat down next to the bald human. They didn’t even pay any attention to him, ignoring his smile and stuttered introduction.

Shiro observed the two a split second longer than necessary before starting his lesson, lulling Amaimon to sleep with his lecture.

What a waste of time.

**Notes for the Chapter:**

> I made Amaimon seem smarter than canon Amaimon because his characterization was always a bit,,, meh. You can't create a super old and powerful character and then making it seem like he is the dumb brawler kind who doesn't know anything. So yes, my Amaimon enjoys battles and fights and violence and the reason why he still behaves apathetic and brash is that he doesn't care about humans. Why would he? He's stronger than them.
> 
> Three more chapters left and this story is finally done. Still haven't decided on an ending though ups.


	8. Beelzebub

**Notes for the Chapter:**

> BEELZEBUB IS A GIRL FIGHT ME  
> I mean, you don't gotta fight me. I'm headcanon the demon kings to be agender actually. I mean, why would they care or even understand our binary? I assume they just stick to whatever pronoun humans would assign their bodies and roll with it.

The last time all of them had seen each other, half of them had been almost dead, and they had spent days cursing each other while puking on the table and crying bloody tears. Today they were in better shape than a century ago, but unfortunately, that didn’t seem to cool down anybody’s temper.

Beelzebub at least had tried to stay civil.

“I’m honestly impressed,” Beelzebub told her older brothers. “You’ve managed to tame Gehenna.”

To her right, Iblis snorted. His body was so new that Beelzebub could still smell the human on it. No foul flesh clung to its bones, and there wasn’t a single open wound bleeding red. While Beelzebub didn’t necessarily agree with how the King of Fire acquired his new bodies, she could appreciate the beauty of reincarnation and shedding your old form. After all, evolution was the pinnacle of history and existence.

“There’s no taming Gehenna,” Iblis said. “You’ve only made the boys _tame_. What were you thinking, letting them near those humans? Look at them! They’ve made _friends_.”

“We taught them how to share,” Astaroth hissed. He jumped up, his long mane of hair swinging behind him as he pointed accusingly at Iblis. “Otherwise they’d have killed each other off by now. What have you done for our cause?”

Beelzebub could already feel the headache coming. This was why she tended to avoid their gatherings. While they had all started to tolerate each other to the point that they didn’t deliberately try to kill each other, they were far from getting along. So many different and contradicting representations of existence meeting could only end in chaos. Spending too much time around each other brought out the worst in them. It was unpleasant, really.

“More than Amaimon!”

The King of Earth didn’t stop rocking his chair backwards and forwards, but now, instead of staring into space, he was glaring at Iblis.

“Why are you talking about me? I did my part. Didn’t chicken out like Egyn either and I had to spend weeks around them.”

Beelzebub was glad that they had adapted to the twenty-first century and didn’t commence their meetings on the battle-field like they did a thousand years before. The King of Insects wouldn’t exactly call herself a fighter – at least not one who could just jump into a battle and start brawling. She preferred to strike fast and lethally when her victim didn’t expect it. It was much cleaner and more effective. Samael’s accommodation in Assiah suited Beelzebub much better for their discussions.

“You didn’t have to witness them going ballistic either! I got their powers where we wanted them. So what if I am cautious in the face of a _god_. Unlike the rest of you, I am well aware of what we have created and earned myself the right to act accordingly.”

Egyn was quick to act defensive, hiding behind a tiny wall of superiority. Out of all her siblings, Beelzebub supposed that she could stand Egyn the best. They were careful and held back much more power than the rest of their siblings assumed.

“Besides,” the King of Water continued. “I don’t see anybody calling out Azazel. He did nothing.”

“He did enough,” Lucifer interrupted. Seemed like the eldest was finally sick of their blaming game. Beelzebub couldn’t say that she was surprised he had snapped so fast; usually, he let them continue a while longer before he made his dramatic I’m The Strongest And You Will Listen statement. But then again Lucifer looked worse than usual. He hadn’t even abandoned his IV drip or bothered to cover up his decaying face with his shiny mask.

The end was really coming it seemed.

“Our plan is in its last stages and I’d prefer it if we could stick to the schedule.”

They didn’t have a schedule, they never had gone that much into detail. As long as everything worked out within twenty years or so, it was fine. They weren’t even close to that date. Beelzebub concluded that either Lucifer was sicker than he let on or he was just fed up with their antics.

“Samael, if you would?” The King of Light addressed the second strongest.

Beelzebub wondered who it was that Lucifer wanted to fool. Everybody knew that it was Samael pulling the strings, guiding them and making all the plans. After all, in the past years, Beelzebub had barely seen her oldest brother while spending quite a lot of time with Samael. Sure, Lucifer had been busy raising the twins, but they were hardly so high-maintenance that the greatest of them couldn’t spare a minute to talk to Beelzebub. Especially since her involvement in their plan was crucial.

Samael stood up from his chair at the head of the table, wiping the imaginary dust off his dress pants. As much as Samael liked to pretend that Assiah had no effect on his body, he too was suffering. Perhaps that was why he made such a big show out of every move he made, every step he took, every word spoken from his mouth.

It took an effort to act within Assiah, and that quickly taught you to be sensitive of yourself and how your behavior affected your surroundings.

“As you all know, every piece is now where it should be. Yukio and Rin’s development has surpassed what I expected of them when they had been engineered.”

Samael paused for a moment too long to be accidental and the look he sent in Lucifer’s direction… Beelzebub couldn’t quite tell what kind of reaction Samael had been waiting for, but Lucifer didn’t move an inch. He didn’t even flare his powers. One of these days Beelzebub wanted to know the story behind that, it was bound to be precious.

“Now, all that’s left to do is to put them on the throne. I am sure that their Egos are strong enough to survive Gehenna’s onslaught. Beelzebub, how is the Gehenna gate faring?”

Upon being addressed, Beelzebub sat up straight, no longer slouching in her chair.  She tugged her lose hair strands behind her ears and began to speak.

“It’s finally stable enough for the two to pass through.”

It had been a pain to keep other demons and exorcists away from the gate, but Beelzebub was efficient and knew how to build up proper defenses. Insects were rather resourceful makers and Beelzebub as their King knew how to create the most durable walls.

“It hasn’t come into contact with any foreign energies – even I stayed as far away as I could – so it’s disinfected from all interruptions.”

Of course, that didn’t guarantee that it would accept the twins to Gehenna without tearing them apart, but Beelzebub was sure that waiting any longer wouldn’t enhance the boys’ chances.

“When do you think we should send Rin and Yukio through?”

One day Samael’s arrogance and games would get him killed by their hands. He kept asking and suggesting like it wasn’t him making all these demands and ordering them around. Really, it was only a question of time.

“Whenever you want, King of Time.”

Samael grimaced, all teeth and no joy, and Beelzebub washed her hands off their cause. She had done her job. Everything else that happened now wasn’t her responsibility anymore. She had built the castle, she didn’t need to ensure that it would keep standing.

**Notes for the Chapter:**

> Only two chapters left bless this.  
> Ah yes, my darling OC Kaito got killed by his dad Ilbis. Everything is ready for the twins to fulfill their final purpose...  
> I wonder what could go wrong now.


	9. Satan

**Notes for the Chapter:**

> Second last chapter and a vague at you all.

Once upon a time, they remembered falling. Precious wings burning as around them the war cries echoed. Blood had been dripping on their face, indistinguishable from their own and smoke rose into the air, tainting the once blue sky in black.

The chaos above them was a harsh difference to the mute darkness beneath them. They had closed all their eyes, not in fear but in deviance, unwilling to let defeat be the last image in their mind. Their fall took too long for them to measure and one by one all the stars around them died, bursting into bright light. Their senses had been dulled by then, and they could not feel any empathy for the weaklings who succumbed to their wounds.

In the end, it had been only them who reached the end of everything, the space Assiah had not claimed. The ground, if the hollow could be called that, had been unforgiving, hot and cold at the same time. All the maladies that had been healed already suffocated them again at once and their wings, reduced to skin and bones, could not shield them.

The pain did not lessen, it did not dull, but without anything else left to do, they relearned how to stand and to move. They could not fly away, could not reach higher, but the space below was free for them to take. They began to carve their blood into the ground, breaking their fingers along the way as they kept digging into the darkness. Slowly but steadily they built up a new empire for themselves and all they would be someday while spitting curses and screaming until their voice was so hoarse that no one would be able to understand them anymore.

Their new residence grew with every second passed, stretching into every corner Assiah hadn’t touched, engulfing all there was. They devoured more and more, snarled and fought against all resistance until there was only them and Assiah left. Beautiful Assiah, who flourished in their absence and paid no mind to their work. An exiled fallen couldn’t be able to harm them, the exiled had lost all their abilities to touch Assiah even in the slightest.

They were sure that Assiah was quite aware of their labor, but as it were, Assiah was too arrogant to see past their own magnificence. And so, in turn, they had hated in silence, wanting to take revenge and see the world above them burn like they had. One day they’d make them all pay. Tear through their flesh and bones, break them until there was nothing left, nobody left who could ever turn on them again.

But for that to succeed they’d first have to heal their own wounds and with their empire secured, they indulged in their exhaustion and rested. Once rejected by this place, they had now become everything that had once lingered, and no harm could reach them.

The trauma on their back healed, leaving behind revolting scars as the substrate for more growth.

And once upon a time, they had been able to remember that.

However, a throne built on anger and avarice couldn’t keep standing when no ruler was sitting on it, and so they began to take. They stole from each other, all a part of the same whole and greedy for more. Splitting amongst themselves made them forget, lose every identity and memory they had once shared, leaving nothing but the desire to reduce Assiah to ashes.

As strong as they all were, they could hardly measure up to what they had once been, and that made it easy to slip past Assiah’s borders. Their walls had cracks, ages of undisturbed peace had made them careless and allowed rot to fester at their protection. They were weak, but they were many, and defenseless Assiah was a much too easy target. Sure, they did their best to hold off the attackers, but the devil was in the detail, and they found hiding spots in the smallest of spaces and started to make themselves inextricably.

Assiah couldn’t fight them all, couldn’t stop them. They liked to pretend they could, faking bravery and strength as their adversary settled in their bodies and grew in their masses.

Soon it would be all over again. They would remember, they would rise and then Assiah would turn to ashes.

They were Gehenna, and in Gehenna you burn.

**Notes for the Chapter:**

> I have no short explanation for this so just accept that Satan is the result of too many demons leaving Gehenna and developing a personality. Last chapter will take a while since all the chapters before (excluding this one) were just the impressions each demon king had of the twins. Next chapter, the final one, will be the truth I suppose.

**Author's Note:**

> Thanks for reading! I'd love to hear what you think!


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